Long time reader/lurker, finally made an account; I look forward to participating more in the forum and discussions, and I thank everyone for the information I have gleamed from you all over the years. I am sure I can search through the bagillions of posts about this lens and find this information, but I simply don't have time and am hoping someone will be able to help me out. My apologies for that in advance...
I just ordered a brand new 14-24mm Nikkor and it is my first pro lens purchased at full price other than my 200-400 f4. Leaving aside focus adjustments, I have no experience testing this sort of optic but have heard stories of multiple returns until a flawless copy was finally received. I ordered mine through Amazon.ca which means I have every opportunity I want to return for a proper replacement, but it is up to me to test it properly...
My question(s) is(are) this(these): how or what process should I go about to test this lens and ensure that I have a proper copy? What are the most important things I should be looking out for other than focus accuracy–which is already questionable through the finder with this kind of lens in the first place–and dust/damage? In short, how can I make sure I have a good copy?
I'm super excited about this thing but don't have a lot of cash and really want to make sure I get my money's worth. This is on top of how crazy intimidated I am by that front element and lack of protective filter options! Maybe I should just grab a Wonder Pana and schlap a 145mm UV filter on it...
You need to shoot from a tripod with mirror up/delay/remote release from the center of the chart and dead square on, base iso ( 100/64) .
You can check for decentering by checking the sharpness of the corner charts vs each other, ( I overlay crops in photoshop ) and checking the Cromatic abberation of the corners.
The 14-24 ought to *easily* resolve the central 20 lines ( as long as your printer is good enough )
Another good check is to shoot a starfield, with the camera pointed straight up, to check for corner sharpness and coma performance. However this relies on you being familer with astro photography, so the chart method is a good start.
Ironheart: For sure. If you really want to be precise in that regard, the iPhone's level and compass is a great and convenient tool to make sure you are on point. Pick your planes, schlap your phone on 'em, and rock that high school geometry.
Speaking of schlapping... I used the $500 I saved and bought the Wonderpana system. Shipping was updated and she arrives on Monday. I haven't been sleeping much, and I only regret not saving (a lot) longer for the 15mm Zeiss a little bit...
As for the 15mm Zeiss you will not better the Samyang 14mm
For now, I created a really nice poster of the ISO 12233 pdf using four custom-cut, 13"x24" satin sheets, printed with photo black ink on the slowest highest quality setting. The final cut and assembled poster is just over 22.5" x 37" and looks great. I don't have perfect definition between lines at 20x, but enough to accurately assess sharpness for sure. If you print with matte black ink on the right paper, I am sure better definition could be achieved–at the expensive of durability/risk of smudging, which would certainly be annoying as there is so much black around those edges. There are also the obvious lines from merging pages, but these can be used as further means for assessment.
If you have a 13" wide printer and would like my prepress pdf of the ISO 12233 chart for that page size with crop marks, feel free to shoot me a message. In the mean time, I am anxiously waiting by the door (like a dog) for the lens to arrive while an incredible Fall day passes me by.
I ran tests like crazy on the lens, with my best and most consistent results coming by laying the ISO poster on the ground and leveling out my camera in live view tethered to my PC. A combo of an actual level and using the grid got me as close to perpendicular as possible. While I still need to set up the rig to test at 14mm (tripod was casting shadows so close to the poster), the thing is incredibly sharp. The left corners are a tiny bit better than the right corners, top left being the best, but I did achieve a test or two where that was not noticeable. It is certainly possible that my lens face was not parallel with the poster, as even the smallest deviation could cause such results.
All in all I am so pleased I picked up this lens; I can't wait to get it back out in the field and see how 14mm can push my work. Many thanks to you all for the tips, though I still need to try it out on a brick wall...
Nikon N90s, F100, F, lots of Leica M digital and film stuff.